Conventionally, a commercial transaction system is known which connects to a network such as Internet using a terminal device such as a personal computer, and which enables commercial transaction such as purchase of a product or reservation to use service through, for example, a webpage provided by, for example, a web server. Such a commercial transaction system displays (lists) a so-called banner advertisement on, for example, a predetermined webpage. For example, sellers of products can lead viewers to webpages for selling the products of the sellers by way of links established in banner advertisements.
Meanwhile, a banner advertisement displayed in, for example, a popular webpage has a high advertising effect, and therefore there is a lot of advertisers who desire to display banner advertisements on such webpages. However, an advertisement display area for displaying a banner advertisement on a webpage is limited, and therefore the number of advertisers who can use the advertisement display area is also limited.
Meanwhile, in recent years, a technique is known which switches a banner advertisement to be displayed in a single advertisement display area on a given webpage per predetermined time. Such a technique can display banner advertisements matching a greater number of advertisers in one advertisement display area. Further, Patent Literature 1 discloses a technique which is capable of automatically changing advertisement content which has already been listed only by transmitting advertisement data from a client terminal to a management server.